Detect any html tags

Is it possible to use HTML Purifier just to detect if input string contains any html tags,
without purifying.
I would like to discard whole thing in case if it does, just I don't know how to achieve that.

Then you should store the data verbatim, and escape it as appropriate for the output format (htmlspecialchars for HTML, mysql_real_escape_string for SQL, etc). This means if I do something innocuous like , it doesn't cause the script to reject it.